<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title></title> </head> <body> <button οnclick="commit()">确定</button> </body> <script> function commit(num) { if (num === 1) { return 1 } else if ( num > 0) { return num * commit(num - 1) } } console.log(commit(3)) </script> </html>